Romans 11:23-24

And even they [the unbelieving Jews], if they do not continue in their unbelief, will be grafted in; for God has the power to graft them in again. For if you were cut off from what is by nature a wild olive tree, and against nature were grafted into a cultivated olive tree, how much easier will it be to graft these who are the natural branches back into [the original parent stock of] their own olive tree?